Background: IVF is becoming now the gold standard for solving the problem of infertility, nearly million IVF babies were born. The time of embryo transfer still rises a big question and is still a field of great debate whether to transfer it early as day 3 or wait till day 5 or day 6 to give a good chance for embryo selection. Aim of the work: to determine whether embryo transfer on day 3 versus day 5 versus day 6 shows a significant difference in implantation, clinical pregnancy, live birth, miscarriage and multiple pregnancy rates among women undergoing intracytoplasmic sperm injection. Results: Concerning multiple pregnancy rates day 3 embryo transfer was 7 (14%) in compared to 31 (31%) in day 5 embryo transfer in compared to 13 (26%) in day 6 embryo transfer which still shows significant difference between three groups. There was only slight difference between live birth in three groups, for day 3 we had (14%) 19 (5 twins and 9 single) living babies while for day 5 we had (44%) 70 (26 twins and 18 single) while for day 6 we had (20%) 31 (11 twins and 9 single). Using Pearson Chi-Square there was significant difference between the three groups regarding live birth. There was great difference in success rates and outcome of embryo transfer between three groups.Conclusion: From this study we can conclude that there is significant difference in either pregnancy or delivery rates between day 3 and day 5 and day 6 when patients are appropriately randomized. Delaying embryo transfer to day 5 or day 6 offers advantage to patients undergoing ICSI. Embryos that develop to the expanded blastocyst stage and are transferred on day 5 after retrieval are approximately as likely to implant compared to those for which expansion and transfer are delayed until day 6.